Re: D&RGW tender air valves

I am looking at the Westinghouse Air Brake booklet from 1909 for "The Combined Automatic and Straight-Air Locomotive Brake Equipment." This is the style of locomotive equipment using triple valves and not the #6 Distributing Valve. This system had a triple valve on both the locomotive and the tender. As discussed here a few months ago, even the K-class Mikes that came in the 1920s and 30s were equiped with this out-of date brake schedule instead of the 6-ET.
The diagrams and text talk about two small valves that would be added for mountainous country. One of these valves is on the tender and one on the locomotive. The purpose of these valves, when open, was to make the brakes on the locomotive and tender to only be operated by the straight-air valve and not the automatic valve in the cab.
Under "Instructions for Operating" the following is found:
"6. Bear in mind that the straight-air on the driver and tender brakes is almost as powerful as the automatic brakes on same, and that each should be used with care to avoid rough handing of train, or, in holding down a long grade, loosening of tires on drivers. When the straight-air is used to aid in recharging trains in motion down steep grades, the automatic should be kept inoperative by having the one-half-inch cocks, shown at C and D in Fig. 1, open."
As discussed here a few months ago, even the mikes that came in the 1920s were equipted with this out-of date brake schedule instead of the 6-ET. Probably because all of the enginemen were used to this system.
Brian Norden